Interpretive Summary: Camelina, guayule, lesquerella and vernonia are four alternative industrial crops that are either under limited commercial production or being developed for production in the southwestern USA. Lygus hesperus is an abundance and common pest that affects many crops in the region and can be found on all four of these new crops in the field. It primarily feeds on the flower buds, flowers and fruit of affected crops. As this pest is likely to represent a threat to production of these alternative crops there is a need to establish baseline data on potential harm. We used an observational method to quantify what parts of these four crops that Lygus bugs will feed upon and to what degree preferences for various plants tissue are exhibited. Lygus bugs spent ˜35% of their time either probing (=tasting) or feeding on various reproductive and vegetative tissues of guayule, lesquerella or vernonia, but only 20% on camelina, suggested that they prefer the first three plants. When insects did probe and feed they preferred reproductive tissues, primarily the seed producing structures (floral buds, flowers and fruits) regardless of age or sex. Insects probed and fed more on flower tissue of guayule and vernonia compared with camelina and lesquerella, and more on seed pods of lesquerella compared with seeds of vernonia. When probing and feeding on vegetative tissue, there was generally a preference for stems compared with leaves in all crops except guayule. Results show that L. hesperus will readily feed on the economically important tissues of all crops, and although research has shown that this feeding did not consistently affect lesquerella yield, further work will be needed to determine if such feeding poses a risk to commercial production of camelina, guayule or vernonia.

Technical Abstract:
Camelina (Camelina sativa), guayule (Parthenium argentatum), lesquerella (Physaria fendleri), and vernonia ( Centrapalus pauciflorus [formerly Vernonia galamensis]) are either under limited commercial production or being developed for production in the southwestern USA. Insect pests are a potential economic threat to all these new crops, with Lygus hesperus, the western tarnished plant bug, among the most prominent due to its regional abundance and propensity to feed on reproductive plant tissue. To establish baseline data on this potential pest, behavioral observations of adult females and males, and nymphs of this insect were made in the laboratory. Insects spent ˜35% of their time either probing (=tasting) or feeding on various reproductive and vegetative tissues of guayule, lesquerella or vernonia, but only 20% on camelina. When insects did probe and feed they preferred reproductive tissues, primarily flowers and siliques/achenes, and there were differences in these behaviors relative to crop but not generally to insect stage or sex. Insects probed and fed more on flower tissue of guayule and vernonia compared with camelina and lesquerella, and more on siliques of lesquerella compared with achenes of vernonia. When probing and feeding on vegetative tissue, there was generally a preference for stems compared with leaves in all crops except guayule. Results show that L. hesperus will readily feed on the economically important tissues of all crops, and although research has shown that this feeding did not consistently affect lesquerella yield, further work will be needed to determine if such feeding poses a risk to commercial production of camelina, guayule or vernonia.